Sonographic Evaluation of the Plantar Fascia in Asymptomatic Subjects

Abstract

Plantar fasciitis is a low-grade inflammation of the plantar fascia and perifascial tissues. It is a common cause of heel pain and usually affects middle-aged women, as well as younger, predominantly male, runners (1). The condition is likely related to repeated strain, leading to microtears and inflammation. Imaging is commonly used to confirm the diagnosis, and exclude other causes of posterior heel pain (2).Although MR imaging may be used to diagnose plantar fasciitis, many authors suggest ultrasound is an accurate, simple, and noninvasive technique to diagnose the condition. Previous investigators have reported that the most important diagnostic findings in plantar fasciitis are thickening and hypoechogenicity, and occasionally fluid collections adjacent to the fascia. Wall et al. (3) suggest that a plantar fascia thickness greater than 4 mm is consistent with plantar fasciitis. This value has been used as a reference value in several studies (4-6).To our knowledge, there are no data about the ultrasound appearance of the plantar fascia in asymptomatic subjects. Hence, it is not known if certain commonly used ultrasound criteria of plantar fasciitis might be seen in such a population. If so, this may entail the risk of attributing the patients' symptoms to a reference point where the plantar fascia crossed the anterior aspect of the inferior border of the calcaneus. The measurement points are indicated in the figures by calipers (Figs. 1-3). The plantar fascia was evaluated for echogenicity. It was only considered hypoechoic if its echogenicity was markedly decreased with respect to the subcutaneous heel fat. The plantar fascia was also assessed for presence of calcification defined as markedly hyperechoic foci, with or without acoustic shadowing, vascularity with Doppler, tear, and fluid adjacent to the fascia. The saved images were reviewed by 2 investigators. Statistical analysis was performed using a t-test (independent samples) (IBM SPSS Statistics 20, Armonk, NY). The significance threshold was set at p = 0.05. ResultsA total of 62 plantar fascias in 31 subjects (14 men, 17 women), aged from 17 to 79 years (mean age, 45 years) were evaluated ( Fig. 1-3). The results are shown in Tables I and II. The mean thickness of the plantar fascia in men was 3.7 mm (range, 2.5-7 mm), and in women 3.5 mm (range, 1.7-5.1 mm). There was no statistically significant difference between the thickness of the fascia in men and women (p = 0.21). There was no significant difference between the right and the left foot (p = 0.64).The thickness of the plantar fascia was greater than 4 mm in 4 men plantar fasciitis while other abnormalities may be overlooked and not further investigated. Therefore we decided to evaluate the plantar fascia in asymptomatic subjects with high resolution ultrasound. Materials and methodsInstitutional Review Board approval for our study was obtained and consent from the asymptomatic subjects. They were interviewed to confirm they had not been symptomatic at the sole of the foot. Other exclusion cr...

Effect of Gender, Toe Extension Position, and Plantar Fasciitis on Plantar Fascia Thickness

“…When comparing the plantar fascia thickness between healthy males and females, no significant difference in plantar fascia thickness was found collectively or at any MTP joint extension position (Table 2). Previous studies have also found no difference in plantar fascia thickness between males and females, 10,14,24,38 which is in contrast to other studies that identified males as having thicker plantar fasciae than females. 2,14,34 Huerta and Garcia found that males had increased plantar fascia thickness when measured 1 cm proximal to the plantar fascia insertion, whereas they found no difference among males and females when the thickness was measured at the insertion (ie, anterior border of the calcaneus where the plantar fascia just leaves the calcaneal tuberosity) or 1 or 2 cm distal to the insertion.…”

“…2,3,21,37,38 However, plantar fascia thickness norms for men and women have varied in the literature. Some studies have found no differences in plantar fascia thickness between men and women, 10,14,24,38 whereas other studies have identified men as having increased plantar fascia thickness compared with women. 2,14,34 Gender and its inconsistent relationship in the literature pertaining to plantar fascia thickness is still unclear.…”

Thickness of the plantar fascia in asymptomatic subjects

“…We believe that the few asymmetric values would be partly related to a measurement error since the difference did not exceed 0.20 mm. This symmetry was also found by Gadalla et al [12] This symmetry is preserved even if the thickness of the PF decreases progressively away distally from the insertion. According to the walking activity, the thickness of the PF increased as a function of the daily distance traveled.…”

“…In our study, the BMI also participated as a factor favoring the thickening of PF. On the other hand, the thickness of the PF at the right and at the left side did not vary according to the gender of the participants as found by Gadalla et al [12] while Pascual Huerta and Alarcón García found a variation in the thickness of the PF measured at its insertion and at 1 cm distally according to gender and that he considered related to the difference of certain fibers that would be thicker in men than in women, and he concluded that the thickness of PF in men exceeds 0.42 mm that of women. [4] The thickness of the PF at right and left was symmetrical in 90.3%.…”

On the morphological relations of the Achilles tendon and plantar fascia via the calcaneus: a cadaveric study

“…The former involves connection via connective tissue whereas the latter details patterns within the trabeculae of the calcaneus, which are aligned in the direction of the fascicles from the AT to the PF. Moreover, there is conflicting evidence of correlations existing between traits such as age, sex and body size against the thicknesses and CSAs of the AT and PF [17][18][19][20][21][22] . Conclusively, if there are significant correlations found between the thicknesses or CSAs of the AT and PF, it will provide additional evidence on a morphological relationship between the two structures, furthermore implying a functional one according to the concept of 'structure and function' .…”